1. Field of the Invention
The present invention relates to a woodworking jig and, more particularly, to a woodworking jig comprising a workpiece clamp and router guide members for guiding a router bit during cutting of the workpiece while the workpiece is held by the clamp. The jig is useful for making joints between pieces of wood, and in particular, but not exclusively, for making dovetail joints.
2. Description of the Related Art
In prior art dovetail jigs, it has been common practice to provide a metal or phenolic template, or separate router guide fingers, mounted on top of the jig and serving to support the base plate of a router, while guiding a router bit projecting downwardly past the template or guide fingers. It is a disadvantage of such an arrangement that the template or guide fingers must be sufficiently rigid to support the downward pressure of the router base plate.
One prior art dovetail jig of that type has double-ended guide fingers, each with a male guide at one end and a female guide at the opposite end. If the fingers are uneven, the router tends to be deflected upwardly and downwardly during the cutting of the dovetail pins and tails, causing a step to be formed in the joint. The router is not supported beyond the ends of the fingers. In use, guide fingers are clamped onto guide rails and, to change from male to female guides, or vice versa, the guide rail, together with the guide fingers, must be removed from the jig, rotated and then reinstalled and repositioned on the jig for through dovetails or rotated end-to-end for half blind dovetails. Such an arrangement is complex and difficult to learn, and makes repeatability of the finger settings difficult to achieve. Furthermore, because the fingers are double-ended, and therefore long, the workpiece, which is horizontal, must be clamped relatively far from the end of the workpiece, which makes it difficult to clamp the workpiece rigidly.
It is also common, in prior art dovetail jigs, to clamp a horizontal workpiece down onto a top surface of a jig body and to clamp a vertical workpiece against a front surface of the jig body. When the workpieces have been thus clamped down onto or up against the jig body, the guide finger assembly has to be lowered down onto the top surfaces of the workpieces, adjusted into position and locked in place. This contributes to the complexity of such dovetail jigs and, also, adds to the manufacturing costs.
According to the present invention, there is provided a woodworking jig, comprising a workpiece clamp, a woodworking jig, comprising a workpiece clamp router guide members for guiding a router bit during cutting of a workpiece held by the clamp, a pair of horizontally elongate co-planar router plate guide surface areas spaced apart from one another, an elongate opening between the router plate guide surface areas, the workpiece clamp being mounted below the opening, a guide member support extending along the opening and a plurality of router guide members, characterized in that the guide member support has a row of locating formations distributed along the guide member support and the guide members have corresponding formations engageable with the locating formations. to the locate router guide members in operative positions above the workpiece clamp and below the level of the router plate guide surface areas.
By spacing the locating formations in a uniform manner along the guide member support, the guide members can be easily located at various spacings apart from one another along the guide member support and these spacings can be readily restored when the guide members are removed from and subsequently reinstalled on the guide member support.
The guide members preferably comprise dovetail pin guides and dovetail tail guides which are separate from the dovetail pin guides, and may be readily engageable with the guide member support by snap-action engagement of the guide members onto the guide member support. However, the guide members may alternatively be shaped and utilized for cutting e.g. mortice and tenon joints, box joints, finger joints and decorative joints.